System of electrical distribution.



P. G. HEWITT. SYSTEM OF ELECTRICAL DISTRIBUTION. APPLICATION F'ILBD AUG. 3.1, 1905.

Patented Nov. 5, 1912.

3 SEEBTSSHEET 1.

Patented Nov. 5, 1912.

3 SHEETSSHBET 2.

1% 14 (mom P. C. HEWITT. SYSTEM OF ELECTRICAL DISTRIBUTION. APPLICATION FILED AUG.31,1905.

Patented Nov. 5, 1912.

3 SHEETS-SHEET 3.

UNl'lll ll) STATES PATENT OFFICE.

PETER COOPER HIZW'ITT. OF NEW YORK. N. Y, ASSIGNOR '10 COOPER HEWITT ELECTRIC COMPANY, OF NEW YORK. N. Y.. A CORPORATION OF NEW YORK.

SYSTEM OF ELECTRICAL DISTRIBUTION.

Specification of Letters Patent.

Original application filed July 30. 1904. Serial No. 218,851. Divided and this application filed August 31, 1905. Serial No. 276,487.

To ail whom it may concern. Be it known that I, Pmnn Coornn l-Inwrcr, a citizen of the United States, and resident of New York, county of New York, State of New York, have invented certain new and useful Improvements in Systems .of l llectrical Distribution, of which the follow ing is a specification.

The principal object of my invention is to obtain pratatically continuous alternating currents of very high frequency with cone paratively small variations of intensity of the successive alternations or waves. To ef fect this object I utilize the high frequency pulsations or alternations which are setup by capacity abruptly discharging through inductance. Such discharge ceases to be oscillatory when R is greater than 4 L/( L being the inductance, (l the capacity, and It the resistance, all losses Whether by friction. conduction, induction, convection, or radiation being reckoned as resistance. Yet in many relations it is almost essential to ultimate purposes and objects that the energy of the condenser discharge be utilized by immediate transfer out of the oscillating circuit. For instance, in wireless telegraphy or telephony if the aerial has large capacity and readily radiates large amounts of energy, the oscillations of a condenser discharge circuit feeding the same, may rapidly weaken to a point Where the potential is insutiicient to break down the dielectric of the spark gap or equivalent discharge device, and the current soon ceases to oscillate. Moreover, with most such apparatus, there are practical difficulties which limit. the rate atwhich recharge and dis ruptive red-ischarge can be effected. In order to meet such conditions and to secure a persistent or continuous high frequency alternating current of the class described-I have arranged a plurality of oscillating circuits adapted to cooperate synchronously and in phase to supply a succession of fresh impulses or discharges at intervals as short as may be necessary to maintain substantial continuity and even uniformity of the high frequency alternating currents or oscillations referred to. I may, of course, arrange matters of proportion and adjustment. in such manner as to produce any desired ap proximation of continuity or uniformity. The broad feature of causing two or more oscillatory circuits to energize the same consumption circuit successively or through different periods, is independent of the nature of the prime source or sources of power, provided only that each oscillatory circuit receives suitable charges of energy at the proper times, and though, as is well known in the art, it is possible to employ for such purposes ordinary direct currents of comparatively low voltage, or even rectified alternating currents of higher voltage. I have made the important discovery that comparatively low frequency alternating, fluctuating, or intermittent currents or charges mav be. utilized for the prime energy supply, without causing appreciable irregularities or discontinuities in the rate of the prime discharges energizing the radiating or other consumption circuit. I accomplish this by employing a plurality of varying or alternating supply currents wherein the periods of ctiicieut' energy output of one supply current are so timed with respect to periods of small or insutlicient energy output. of an other supply current, that the periods of small or insuflicient outputof one supply may be bridged over by the periods of suiticlent energy output of some other supply current. or currents. For instance, by utihzing two or more alternating current supplies having a multiphase time relation in connection with capacity circuits to be energized thereby and by causing the resulting discharges to take effect upon a common consumption circuit, the latter may be supplied with fresh energy by prime discharges taking effect successively atapproximately uniform intervals, Without the intermissions which occur at every zero point of the alternations where a single phase alternating current supply is used. Thus a plurality of fluctuating or alternating currents or pressures of relatively low frequency may be made to furnish fresh energy charges or currents, at an extremely high rate.

Itwill be understood that the expression consumption circuit where used in a broad sense is intended to include not only metallic circuits, closed and unclosed, but also any device or field in connection with which the currents may be usefully applied, such as electromagnetic or electrostatic fields, or etheric or other natural or artificial media of propagation.

My invention is capable of greatly varied applications, but its general character will be more readily understood by reference to the specific embodiments shown in the accompanying drawings, wherein Figures 1, 1, and 3 diagrammatically illustrate various forms of my invention. Figs. 2 and 4 are diagrams indicative of the phase relations of Figs. 1, 1 and 3 respectively. Figs. 5 and 6 are diagrammatlc views illustrating means for multiplying frequencies, said means being shown as applied to the frequencies produced in the apparatus of Figs. 1, 1, and 3. C

The primary energy is preferably derived from a multiphase source, which may be a rotating field generator A. The primary energy may be of any desired frequency, as, for instance, 10,000 periods, or a greater or less number, as may be found desirable or consistent with good engineering practlce. It will be understood that a frequency of 10,000 periods is'a high frequency as compared with frequencies commonly employed for commercial purposes; but is a low frequency as compared with frequencies commonly employed for wireless telegraphy, telephony, or other special purposes.

The source of the primary energy may be of any known or desired type. The coils B, B B etc., each receive energy at thelr own particular times. The coils are preferabl even in number and symmetrically place When thus arranged, the two coils directly opposite each other, as, for instance, B, B Fig. 1, receive energy at the same tlme and so far as concerns the functions of producing a multiplied frequency must be reckoned as one coil if connected in phase, so that with six coils as shown, there are but three available phases. It is of course obvious that the total time period of the retating field A may be subdivided into any number of periods corresponding to the number of pairs of coils used;

The energy fluxes set up in the coils B, B B etc., may be utilized as follows: The terminals of the coil B, for instance, are electrically connected through condensers C, C The capacity of the condensers C, C, is then adjusted until the circuit B, C, L, 25, L C B is resonant to the desired frequency. The simplest case is where this fre quency is the same as that of the rotating field, which, as stated, may be 10,000 periods more or less. 1 The spark gap or other discharge device S is then adjusted across the condensers. The desired adjustment of the and of the various tuning devices, is determined by trial. I find that in practice I may make adjustment of inductance at L, L without greatly disturbing this resonance. Such changes of inductance are made for the purpose of tuning the oscillatory circuit S, C, L, t, L, C, S to a frequency much higher than the 10,000 frequency of B. This higher frequency in the case of the arrangement of Fig. 1, should preferably be 3, 9, 15, or 21 times the frequency of A, as will be explained. If the slight change of inductance at L and L necessary to effect tuning to high frequency, materially affects the resonance of the 10,000 period circuit including B, correction may be made by slight additional adjustment of the condensers C, C. For convenience, the 10,000 period circuit may be termed B0 and that of the higher frequency SO.

All of the circuits, B0 and SO BO and so, B 0 and so, 12. 0 and so, BO and S 0, B 0 and S() are preferably electrical duplicates and are usually tuned and adjusted respectively to the 10,000 frequency of B0 and the 30,000 or 90,000 frequency of SO, though it will be evident that the tuning of B0 BB, B B", etc., to the lower frequencies, may be omitted. These circuits which are in a sense independent, are all connected to the terminals of the primary t by the leads 1, 2, so that said primary t 1s common to all and in series with each. In general, it will be noted that the amount of inductance LL in circuit 0 is somewhat greater than the corresponding inductance in circuits 0, O O 0, and This is because the latter five circuits include the inductance of the comparatively long connections 1, 2, leading to the primary of the transformer, whereas 0 is connected almost directly to the primary and the inductance LL must be greater in proportion to the lengths of the leads 1, 2.

It is preferably to connect diametrical and therefore simultaneously energized circuits as BO, B 0 in phase, as in Fig. 1' and adjacent pairs of coils should be connected oppositely so as to establish the odd number phase relations hereinafter described in connection with Fig. 2. When this is done, after the manner indicated in Fig. 1, one oscillation circuit SO may be utilized for both B and B the condensers C C inductance LL and discharge device S being omitted and B connected directly to the terminals of B. The latter arrangement has advantages, for with two circuits SO, S 0 in phase, as in Fig. 1 there is sometimes a possible tendency for S, S to discharge successively as shown in dotted lines in Fig. 4, instead of together as shown in Fig. 2.

In Fig. 1 I have shown an auto-transformer with its primary 2. in inductive relation with the secondary t a ratio adjustment being provided at t. The consumption circuit in this case is an oscillator grounded at G and provided'with an elevated area V such as is commonly used in wireless telegraphy. This oscillator is tuned to the frequency of SO preferably by making its electrical length equivalent to of the length of a wave of that frequency.

\Vith the apparatus of Fig. l I may attain my object of uniform continuous high frequency alternating current quite perfectly, or l may arrange matters to produce any desired approximation of continuity or uniformity. This will be quite evident by reference to Fig. 2 whereinthe phase relations of the voltages in the coils are indicatcd by the elemental or component curves li-- l B B and li -B. Vith this 3- phase relation of voltage having a frequency of 10AM). I may bring in a fresh supply of encrgv by condenser discharge every half wave or half cycle of the higher frequency by tuning the oscillatory circuits SO, S 0, etc.. to a periodicity three times that of the rotating field. It will be understood that discharges at the. rate of nlnetythousand per second, as indicated in Fig. 2, are above the limit of audibility, and that the sound heard in a telephone used as an indicating instrument at the receiving station, will be the sound of interruptions or variations of radiation representing the signal. lVlth a lower periodicity for the multiphase generator and with a higher frequency for the oscillatory circuit, the adjustment of the spark gap is preferably such as to preserve the d scharge frequency above the limit of audihility. If a higher periodicity is desired, said oscillatory circuits SO, S 0 etc., may be tuned to a frequency 5) times that of the generator, in which case the oscillations will be reinforced in phase by fresh condenser discharge every wave and a half. Similarly St) may be tuned .to a frequency 15 or 21 times that of the rotating field where much higher frequencies are desirable and the condenser discharges will always be in phase,

'but the number of alternations in between will. of course. increase proportionally. In prcportioning and adjusting the time period of the discharge circuit, the rate of supply of charging energy, and the breaking down voltage of the discharge device, to get the special conditions indicated in the diagram matic views, it will be found that more than one discharge per half cycle of each phase of the generator may he produced; but multiple discharges per half cycle are often dosirable and may be used to advantage. They may be made most numerous where the oscillatory frequency is a high multiple of the generator frequency, or where the wave is tlat topped, as hereinafter mentioned in connection with Flg. 2.

It will be obvious to any one skilled in the art that the circuits of the coils are to a certain extent independent, the essential interdependentrelation being one of time. If the frequency and the phase relations of Fig. 2, for instance, are attained, it is comparatively unimportantwhether it is by coils of one and the same rotating field or not. F or instance, three similar alternating generators mounted in proper angular relation on a single shaft, or otherwise synchro- .nousl v rotated in proper angular relation,

would answer the purpose. In such case it would be possible to have such generators suitable different odd multiples of one frequency instead of having them of the same frequency.

\Vith the preferred arrangement, the secondary circuit, which is to be supplied, may serve as a synchronizer or regulator, particularly if it be itself a persistent oscillator.

It oscillates in the periods of the higher frequency and reacting on its primary in exact phase it serves to determine the instant of maximum charge of the condensers as exactly coincident with both the crest of a prime wave and the crest of an oscillatory wave. This steadying effect may be so great that where, as in Fig. 3, only two pairs of coils are used and they are in quadrature so that no oscillation or continuous alternating frequency can be found whereof the crests of oscillations will coincide withall of the crests of the prime energy wave, nevertheless the instant of maximum potential on the condensers may be determined as coinciding with the crests of oscillations rather than with the exact crests of the primewaves. This is illustrated in Fig. 4 wherein B 13 and BB indicate the phase relations of the rotating field coils. By trial it will be found that there 1s no oscillation frequency which will give crests in phase with the exact crest in phase with B 13 at the other crest 11 and BB at the other crest 12. In general it will be found that an even multiple of the prime frequency as 0 will be in phase at the two adjacent crests on the same side of the ordinate but will be out of phase with the next.

two crests on the other side of the ordinate. An odd multiple will be in phase with all crests of BB and exactly out of phase with all crests of B 13 Nevertheless if the sec ondary circuit be a very persistent oscillator it will serve to determine the instant of maximum potential on the condensers at the crests of the condenser oscillation as shown at 0 The reason ofthis is that the maximum potential of O at the instant corresponding to 10 added to the potential of BB at the instant will be greater than the potential of BB alone at instant 10 and similarly the potential of 0 plus the potential of B B at instant 11 will be greater than the potential at instant 11. This slight shifting of the instant of sparking from the instant of maximum potential of the prime voltage may be facilitated by so designing that the prime wave will be comparatively fiat topped.

WVhere the secondary circuit is a good v of curve B B? at 9 and BB at 10 and yet he oscillator or where the energy is not transferred too rapidly from the condenser circuits to the secondary the principle explained in connection with Figs. 3 and 4 may be applied in a specifically different way. That is to say, the coils BB etc., may be connected in opposite phase to the primary 2. of the transformer as indicated in dotted lines on Fig. 4 and the maximum potential on the condenser of circuit of coil B will occur at instant 10" at the crest of a Wave of oscillation 0 and not exactly at the crest of B but a little later. The reason is as before namely that the potential of B at instant 10 is the potential of a crest of 0 plus the potential of B a short time before or after the crest and this sum is considerably greater than the potential of B alone even at the exact crest 10. Similarly the potential at instant 11 being that of crest O plus that of BB is greater than BB at crest 11.

\Vith an odd number of coils or with an odd number of pairs of coils as in Fig. 1 exact synchronism of phase may always be attained even with a sharp wave. For instance with 5 pairs of coils the frequency of B0 should be either 5 or 15 times A accordingasa prime condenser discharge is desired every half wave, or every wave and a half. So for 7 pairs of coils the frequency of BOshould be 7 or 21 times that of A; for 9 pairs of coils 9 or 27; etc. For a greater number of waves between prime condenser discharges matters may be arranged by selecting suitable odd multiples of the above numbers as 45, 63, 81, etc., respectively. In the practice of wireless telegraphy, how.- ever, intervals between discharges greater than one and a half waves are not desirable.

This will be evident from the fact that both selectivity and power effects in the receiver may be greatly improved resonance and l good resonance effects are lmpossible unless a considerable number of oscillations succeed each other continuously and synchronously. Otherwise the energy is dissipated before it. has time to build up and accumulate. So far as can be determined the number necessary to good results is not less than ten or twelve waves. It is also desirable't'he largest possible amount of energy be radiated in each wave. A good transmitting capacity area will radiate a very large fraction of the energy supplied to it in about a wave and a half and for that reason fresh condenser charges should supply energy at intervals not greater than this. Another factor in wireless telegraphy is the fact that the practicable height of grounded radiating wires is limited and that the frequencies of which the practicable aerial is a quarter wave length is high; that is of the order of 1,000,000. Another factor is that the speed of rotation of the generator field A-is limited by practical conditions as is also the number of pairs of coils BB. With these various considerations as factors I preferred in some cases to limit rotations of field to about 10,000 and the number of coils or pairs of coils. and the corresponding phases from BB B etc., to three or five. Among other things this limits the number of circuits B0 S0, etc., to be tuned. I also prefer to arrange for a fresh condenser discharge every wave and a half. This with three phases as in Fig. 2 gives a frequency of 90,000 on the primary. This frequency is again raised by means shown in Fig.

Tn Fig. 5 the secondary 2f of transformer 25 is part of a circuit exactly similar to B0, S0 except that #0 is tuned to 90,000 and SO is tuned to an odd multiple of that frequency or preferably 270,000. This latter circuit is in turn a primary to supply currents of 270,000 frequency to a third circuit 0 0 of the same type tuned correspondingly. That is to say, 25 0 is tuned to 270,000 and S 0 to 810,000. In each of the latter circuits the condenser discharge frequency is three times the charging frequency and a prime condenser discharge comes in every wave and a half. Thus from the retating field tothe aerial, there is no point in all the steps of frequency from 10,000 to 810,000 where the alternating energy is not maintained practically continuous by fresh prime discharges at intervals in no case greater than a wave and a half.

If it is desirable that the frequency be doubled instead of tripled the arrangement #0 of Fig. 6 may be substituted for one or more of the circuits 190 22 0 in one direction only. This is accomplished by arranging asymmetric resistances or valves R R in the leads of one condenser circuit and R R in the other. These may be vapor tubes as diagrammatically indicated. The two circuits S"O S 0 are tuned to twice the frequency of t and by this means each half wave becomes a complete wave or waves of twice the primary frequency. The two sets of oscillations may be used separately or may be connected in phase to a common winding as shown'at When used separately the vapor tubes R, R are necessary only in one side of the condenser circuits.

As shown in Fig. 1, a condenser may be placed in shunt to the transformer winding and so adjusted as to give this circuit the same periodicity as that of the vertical or sending conductor.

The word multiphase is used herein to include Q-phase, 3-phase, as Well as phases of greater number.

While practically perfect continuity and uniformity of the high frequency currents illustrated in Figs. 2 and 4 are particularly useful for wireless telegraphy and are preferable where sharp tuning is desired, it is nevertheless evident that for some purposes uniformity is not so important as continuity, and that for many purposes neither continuity nor uniformity is essential, provided the cycles of nonuniformity or discontinuity .follow each other at a rate too high for audibility', or, more accurately stated, at a frequency higher than the frequencies which the telephone or other receiver is able to translate into sensible indications or effects. With such frequencies listening in with the telephone is impossible. Thus, high frequency irregularities may be for many purposes practically useful apm-oXimations of continuity and uniforn'lity. It follows that it is not always necessary to have the high frequency current an exact multiple of the generator frequency, especially where the high frequency is much higher than that of the generator.

The present application is a division of applicants case Serial Number 218,851, filed July 30th, 1904, in which case are claimed certain aspects of the present invention.

I claim. as my invention:

1. The method of generating high frequency currents or impulses which consists in charging a plurality of oscillatory cir cuits and discharging said circuits successively.

2. The method of generating high frequency currents or impulses which consists in charging a plurality of oscillatory circuits and discharging said circuits according to a predetermined time relation.

3. The method of generating high frequency currents or impulses which consists in charging a plurality of circuits including a capacity and a discharge device, up to the voltage of discharge successively.

4. The method of generating high frequency currents or impulses which consists in charging a plurality of circuits including a capacity and a discharge device, up to the voltage of discharge successively according to a predetermined time relation. v

5. The method of generating high frequency currents or impulses which consists in charging a plurality of oscillatory circuits and discharging said circuits successively, the periodicity of said discharge being a multiple of the periodicity of the charging voltage.

6. The method of generating high frequency currents or impulses which consists in charging a plurality of oscil. i-tory circuits and discharging said circuits tccording to a predetermined time relation, the periodicity of each discharge being a multiple of the periodicity of the charging voltage.

7. The method of generating high frequency currents or impulses which consists in charging a plurality of circuits including a capacity and a discharge device, up to the voltage of discharge successively, the periodicity of each discharge being amultiple of y the periodicity of the charging voltage.

8. The method of generating high frequency currents or impulses which consists in charging a plurality of oscillatory circuits, discharging said circuits successiyely,

the periodicity of said discharges being a multiple of the periodicity of the charging voltage and finally causing the discharges to energize the same conductor.

9. The method of generating high frequency currents or impulses which consists in charging a plurality of oscillatory circuits, discharging said circuits according to a predetermined time relation, the periodicity of each discharge being a multiple of the periodicity of the charging voltage and finally causing the discharges to energize the same conductor.

10. The method of generating high frequency currents or impulses which consists in charging a plurality of circuits including a capacity and a discharge device up to the voltage of discharge successively, the periodicity of each discharge being a multiple of the periodicity of the charging voltage.

11. The method.v of generating high frequency currents or impulses which consists in charging a plurality of circuits including a capacity and a discharge device, up to the voltage of discharge successively, the periodicity of each discharge being a multiple of the periodicity of the charging voltage, and finally causing the discharges to energize the same conductor.

12. The method of generating high frequency currents or impulses which consists in charging a plurality of circuits each into the discharge point with alternating voltages according to a regular multiphase time relation, the-discharge periodicity being a multiple of, the charging frequency.

13. The method of generating high frequency currents or impulses which consists in energizing a plurality of circuits each including a capacity and a discharge device, to the discharge point with alternating voltages according to a regular multiphase time relation.

14. The hereindescribed method of pro ducing electric oscillations in a main oscillatory circuit which consists in charging and discharging a number of auxiliary oscillatory circuits in orderly sequence and causing the discharges in said auxiliary circuits to affect the main circuit to throw the same into continuous oscillation.

15. The method of generating high frequency currents or impulses which consists in energizing a coil or winding with alternating voltages, charging therefrom a capacity circuit resonant with said winding to the frequency of the alternating voltage and discharging said capacity through a circuit tuned to a frequency which is a multiple of the frequency of the charging voltage.

16. The method of generating high frequency currents or impulses. which consists in energizing a coil or Winding wlth alternating voltages, charging therefrom a circuit containing a condenser resonant with said winding to the frequency of the alternating voltage and discharging said capac ty through a circuit tuned to a frequency which is an odd multiple of the frequency of the charging voltage.

17. The method of generating high frequency currents or-impulses which consists in energizing a coil or winding by alternat ing voltages, charging thereby a condenser circuit in one direction only, and discharging said condenser through a circuit tuned to a multiple of the frequency of the discharging circuit.

18. The method of generating high frequency currents or impulses which consists in energizing a winding by alternating voltages, charging thereby a plurality of condenser circuits, in opposite directions and each in one direction only, discharging each condenser through a discharge circuit tuned to a multiple of the frequency of the alternating voltages and superposing in phase the energy of said discharges.

19. The method which consists 1n energizing a plurality of similar oscillatory circuits by a rotating field generator operat 1ng to charge said circuits, discharging said circuits successively, the discharge perlodlclties all being a multiple of the periodlcity of the generator, and causing the discharges of said circuits to energize the same conductor.

20. The method which consists in energizing a plurality of oscillatory circuits by a rotating field generator, discharging said circuits according to a predetermined time relation, the discharge periodicities all being multiples of the periodicity of the chargin voltage, and causing the discharges of said circuits to energize the same conductor.

21. The method which consists in charging a plurality of circuits each including a capacity and a discharge device, by a rotating field generator operating to charge said circuits up to the voltage of discharge successively, the discharge periodicities all being the same multiple 0 the periodicity of the charging voltage.

22. The method which consists in charging a plurality of circuits each including a capacity and a discharge device by a rotating field generator operating to charge said circuits up to the voltage of discharge successively the discharge periodicities all being multiples of the periodicity of the charging voltage, and causing the discharges of said circuits to energlze the same conductor.

nating current of low requency and apply- 23. The method which consists in charging a plurality of circuits each including a capacity and a discharge device by a rotating field generator operating to charge each of said circuits tq the discharge point with alternating voltages according to a re ular multi-phase relation, the charge perio s all being multiples of the discharge period.

24. The method of generatlng high frequency alternating currents which consists in successively discharging a plurality of capacity circuits having the same time period and utilizing the oscillations initiated by the successive discharges each to reinforce the preceding.

25. The method of generating continuous alternating currents which consists in generating a plurality of separate alternating currents of the same frequency but fluctuating successively, utilizing said currents to charge capacity circuit each tuned to a frequency which is a multiple of the frequency of the charging current, discharging said capacity circuits successively during a half quency impulses at a high rate, which method consists in generating multiphase alternating current of low frequency and applying energies of each half cycle of each phase of said multiphase alternating current to energize a common circuit.

28. The method of producing high frequency impulses atahigh rate, which method consists in generating multiphase alternating current of low frequency and applying energy therefrom to a common consumption circuit a plurality of times for each half cycle of each phase of said multiphase current.

29. The method of producing high frequency impulses at a high rate, which method consists in generatin multiphase altering the energy of said currents to an OSClllatory circuit to produce oscillations thereof and then reinforcing said oscillations by energy of each half cycle of each base of said alternating current from sai multiphase source.

30. The method of producing high frequency impulses, which method consists in generating a plurality of alternating supply currents or energies, and applying the energies of each of said supply currents to a common consumption circuit according to a multiphase time relation, so that the fresh the other supply currents.

31. The method of producing high trequency impulses at a high rate, which method consists in generating a plurality of alternating supply currents or voltages of relatively low frequency and applying the energies of each said first mentioned circuit, according to a multiphase time relation.

32. The method of generating high frequency impulses at a high rate, which method consists in generating a plurality of currents or voltages, varying according to a time relation sopredetermined that the periods of eflicient energy supply of one of said supply currents occur during the periods of smaller supply of another supply current, and operatively applying to a commonconsumption circuit the energy of each said varying supply currents or voltages during their respective periods of efiicient energy supply.

33. The method of generating high fre quency impulses at a high rate, which method consists in generating a plurality of currents or voltages, varying according to a time relation so predetermined that the peof said supply currents to riods of etficient energy supply of one of said supply currents extend substantially throughout the periods of smaller supply of another supply current, and operatively applying to a common consumption circuit the energy of each of said varying supply currents or voltages during their respective periods of efiicient energy supply.

34. The method of generating high frequency impulses at a high rate, which method consists in generating a plurality of low frequency supply currents or voltages, varying according to a time relation so predetermined that the periods of efficient energy supply of one of said supply currents extend substantially throughout the periods of smaller supply of another supply current, and operatively applying to a common consumption circuit the energy of each of said varying supply currents or voltages during their respective periods of etlicient energy supply. I

Signed at New York, in New York and State of New day of August A. D. 1905.

, PETER COOPER HEWITT.

Witnesses:

WM. H. CAPEL,

THOS. H. BROWN.

the county of York this 29th 

